Influence of Off-resonance in myocardial T1-mapping using SSFP based MOLLI method

Peter Kellman, Daniel A. Herzka, Andrew E. Arai, Michael Schacht Hansen

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Myocardial T1-mapping methods such as MOLLI use SSFP readout and are prone to frequency-dependent error in T1-measurement. A significant error in T1 may result at relatively small off-resonance frequencies that are well within the region without banding artifacts. Methods. The sensitivity of T1-estimates based on the SSFP based MOLLI sequence to errors in center frequency are calculated by means of a Bloch simulation and validated by phantom measurements. Typical off-resonance errors following local cardiac shimming are determined by field mapping at both 1.5 and 3.0T. In vivo examples demonstrate the artifactual appearance of T1-maps in the presence of off-resonance variation. Results: Off-resonance varied 61.8 ± 15.5 Hz (mean ± SD, n = 18) across the heart at 1.5T and 125.0 ± 40.6 Hz (mean ± SD, n = 18) at 3.0T. For T1 = 1000 ms, the variation in T1 due to off-resonance variation was approximately 20 ms at 62 Hz, and > 50 ms at 125 Hz. Conclusions: Regional variations due to the inability to completely shim the B0-field variation around the heart appear as regional variation in T1, which is artifactual.

Original languageEnglish (US)
Article number63
JournalJournal of Cardiovascular Magnetic Resonance
Volume15
Issue number1
DOIs
StatePublished - 2013

Keywords

  • Error
  • MOLLI
  • Off-resonance
  • SSFP
  • Shim
  • T1 map

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine
  • Family Practice

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